Connecting blocks for telephone systems are used in a variety of locations and the design of any particular block depends upon its use. For use in central office locations, connecting blocks comprise a housing carrying a terminal support member through which a matrix of electrical terminals extend. Incoming conductor wires extend to the terminals on one face, i.e. the rear face, of the support member and outgoing conductor wires extend from the terminals at the other or front face. The housing conventionally has side walls extending between a front and a rear of the housing and at the front of the housing the terminal support member is carried. The connector block is normally mounted upon a central office framework by screws passing through a rear plate of the housing and into a framework member. It is a long established problem with connecting blocks that difficulty has been found with mounting the blocks upon the central office frameworks because the screw positions tend to be virtually inaccessible for manual screw location. An unwarranted amount of time is therefore spent in mounting connector blocks upon central office frameworks and also in dismounting them. The difficulty is increased by the obstructed presence of cables and conductor wires passing around connector block positions and also through the connector blocks during mounting and dismounting processes.